In a conventional activated gas generation apparatus, a metal electrode such as an Au film may be formed on a dielectric electrode containing ceramics or the like as a constituent material to form an electrode constituent part. In such an apparatus, the dielectric electrode in the electrode constituent part is a main component, and the metal electrode formed thereon is dependent.
One of the conventional activated gas generation apparatuses is a activated gas generation apparatus in which a disk-shaped electrode constituent part is used; and a source gas penetrating from an outer peripheral part to an inside passes through a discharge space (discharge field), and is sprayed from only one gas spray hole provided in a central part of the electrode to an outside.
Conventional activated gas generation apparatuses including the above-described apparatuses are disclosed, for example, in Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4.
In the activated gas generation apparatus disclosed in Patent Document 1, discharge is generated between cylindrical electrodes formed inside and outside a cylinder, and a source gas is introduced between the electrodes to generate an activated gas (radical-containing gas). The flow path of the activated gas is squeezed by a blowout port provided at the tip of the cylinder to spray a plasma jet. The plasma jet treats an object to be treated set immediately therebelow.
In the activated gas generation apparatus disclosed in Patent Document 2, a pair of opposing electrodes are provided in a flat plate form, and set in a vertical form, so that a gas is supplied into the electrodes from the upper side toward the lower side, to treat an object to be treated set immediately below. The activated gas generation apparatus having a flat plate electrode structure is comparatively easily grown in size, which enables a uniform film formation treatment to a large area. The similar treatment apparatus in which the pair of opposed flat plate electrodes are set in a vertical form is used for many other applications such as Patent Document 5 or the like, including not only film formation treatment applications but also surface treatment applications. There is also an apparatus using an apparatus structure in which a plurality of pairs of opposing electrodes are stacked and disposed instead of one pair of opposing electrodes (Patent Document 6).
In the activated gas generation apparatus disclosed in Patent Document 3, a pair of opposing disk-shaped electrodes are provided; a large number of pores are formed in a shower plate form in a ground side electrode among the pair of opposing disk-shaped electrodes; and a discharge part is directly connected to a treatment chamber. The electrodes are enlarged, or a plurality of electrodes themselves are provided, and numerous pores are provided, which can provide uniform large-area nitriding. The discharge space (discharge field) itself is near the atmospheric pressure, while the treatment chamber is placed in further reduced pressure state via the pores. As a result, the activated gas generated in the discharge field is transported under reduced pressure via the pores immediately after generation, to minimize its attenuation, so that the activated gas can arrive at the object to be treated in a higher density state.
In the activated gas generation apparatus disclosed in Patent Document 4, a pair of opposing electrodes having a rectangular flat plate shape are provided; gaps are blocked by spacers on three sides; and the gas is sprayed toward one direction in which a gap is opened. A gas spray hole is provided at the tip of the opening part, to blow an activated gas (radical) onto an object to be treated.